This invention relates generally to the field of human fertility. More particularly, the invention relates to an apparatus and method for increasing the success rate in either human artificial insemination or embryo transplanting.
The prior art includes several catheters for use in either artificial insemination or embryo transplanting. Such catheters are typically metallic or relatively stiff elastic. The use of relatively stiff catheters can easily result in a traumatic insertion and cause irritation of the walls of the cervix or uterus. Such irritation brings about the unwanted response of the uterus expelling the transferred sperm or embryo and a failed fertilization effort. In fact, the following observation was made by Aby Lewin et al in a recent article entitled "The Role of Uterine Straightening by Passive Bladder Distension Before Embryo Transfer in IVF Cycles" (incorporated herein by reference) published in Journal of Assisted Reproduction and Genetics, Vol. 14, No. 1 (1997), at page 33:
"A traumatic insertion of the ET [embryo transfer] catheter has long been recognized as a cause of endometrial bleeding and uterine contractions, possibly responsible for the expulsion of embryos from the uterine cavity. * * *"
The technique most frequently used in the prior art is placing the patient in the lithotomy position and grasping the anterior lip of the cervix with a tenaculum and pulling downwardly to straighten the utero-cervical angle in order to introduce a relatively stiff catheter into tile cervix and through the internal os to reach the uterine cavity. The effect of utilizing this position and grasping and pulling the anterior lip of the cervix downwardly results in narrowing and elongation of the uterine cavity, the internal os, and cervical canal. In attempting to negotiate the extra distance and the narrowed passage with a relatively stiff catheter, the chances of causing irritation and/or possible trauma of the walls of the cervix or uterus are quite high, which creates the risk of expulsion of the semen or embryo.
Another serious drawback of prior art catheters is trauma caused by their relative stiffness, as reflected by the force necessary to cause them to bend or to buckle. Such force is provided by the walls of the cervix or uterus and stiffer catheters inherently cause greater trauma. The present invention reduces the force necessary to bend the catheter by 95% as compared to the catheter shown in the Fischl et al U.S. Pat. No. 4,790,814.
The apparatus and method of the present invention minimizes and, in some instances, eliminates the irritation and possible trauma of the walls of the cervix and uterus. According to the present invention, the patient is placed in a position to minimize the distance between the vaginal opening and the uterine cavity, i.e., the patient is placed in a supine position on a flat surface with her pelvis elevated and legs flexed with feet apart. The cervical canal is dilated with a bivalved speculum introduced into the vagina and encircling the cervix. The speculum is opened, causing dilation of the cervical canal and the internal os, and separation of the anterior and posterior walls of the lower segment of the uterine cavity.
According to the present invention, an extremely flexible catheter is utilized. The flexible, soft catheter bends easily if it contacts the wall of either the cervix or uterus, minimizing and possibly eliminating irritation or trauma. The catheter of the present invention bends and buckles in response to a force of only 0.1 ounce. Because of the dilation of the cervical canal, internal os and lower segment of the uterine cavity, the catheter reaches the uterine cavity with little or no contact with the cervical or uterine walls.
The positioning of the patient according to the present invention minimizes the distance between the vaginal opening and the uterine cavity, thereby allowing the uses of a catheter with minimum length, which tends to minimize the contact with and irritation of the cervical or uterine walls.
In addition, due to non-traumatic transfer, it may avoid risk of subsequent added problems due to development of uterine abnormalities.
A primary object of the invention is to provide an apparatus and method for use in human artificial insemination and embryo transplanting which minimizes irritation and/or trauma of the uterine and cervical walls, thereby enhancing the success rate of the fertility procedure.
Another object of the invention is to provide a catheter for use in either human artificial insemination or embryo transplanting which is extremely flexible and which avoids, or at least minimizes, contact with and irritation of the cervical and uterine walls.
A further object of the invention is to provide a method of human artificial insemination and embryo transplanting which minimizes irritation of the uterus and cervical walls and increases the success rate of fertility procedures.
Another object of the invention is to provide a method of human artificial insemination and human embryo transplanting which maximizes the comfort of the patient and which minimizes trauma to the uterine and cervical walls, thereby increasing the fertility success rate.
Other objects and advantages of the invention will become apparent from the following description and the drawings wherein: